Rather than credit it to rule changes, there is an easy argument to be made that today’s quarterbacks are just better and mainly responsible for this higher level of play.

Not only did efficiency hit record levels in 2012 with a league-wide 85.6 passer rating and 2.63 interception percentage, but the volume did as well. Teams set records by averaging 21.2 completions and 231.3 net passing yards per game.

Teams also passed on 57.5 percent of plays last year, which is the highest pass ratio in NFL history.

Are defenses too hamstrung by rule changes, or is this just a case of practice makes perfect? With teams throwing the ball more than ever, the secondary coverage players have not caught up to the talent of the secondary receivers yet.

Rule changes have certainly had an impact with more hits being illegal, and the 2011 kickoff rule has created more touchbacks, which means more yards to gain.

However, this current group of quarterbacks is very unique.

In 2013, there will be seven active quarterbacks with at least one Super Bowl win and all are arguably still in, or just entering, their prime. That situation has never happened before in NFL history.

This does not yet include the standout rookies from last season’s greatest rookie class ever. Rookie success is only increasing as we continue to see the first generation of quarterbacks enter the league after growing up in a football world with a pass-first mentality.

Teams are spending more than ever before on quarterbacks. That’s not just about money, but also in resources. Right now, 27 of the 32 teams have a quarterback that was a top 40 pick in the NFL draft. At least half the teams in the league have a quarterback they personally drafted in the first round.

We can debate the greatness of past quarterbacks all day, but simple math and the history of the league have made it possible for such passing numbers to grow. When you add in talent at the position and a willingness to throw, the record books should be torn apart.

Let’s look at the evolution of NFL passing statistics. As is usually the case, you will find that who is under center is as important as anything.

Passing Leaders: Why So Many 4,000-Yard Passers in Today’s NFL?

Last season 11 quarterbacks threw for at least 4,000 yards, which is another NFL record. Joe Namath was the first to do it in 1967, which remains an incredible feat given it was a 14-game season.

Since then, a quarterback has passed for at least 4,000 yards a total of 110 times. A whopping 36 of those (32.7 percent) have come since 2009. The following chart shows the number of 4,000-yard passers per season:

Why so many as of late?

It comes down to opportunity. For a quarterback to throw for 4,000 yards, he needs to play games and throw passes. Even if he attempts 500 passes, averaging 8.00 yards per attempt is still no easy task. Only seven times has a quarterback finished with fewer than 500 attempts in a 4,000-yard season.

That is why no one threw for 4,000 yards again after Namath until Dan Fouts did it in 1979. He needed the 16-game season, which started in 1978.

The other pivotal change that year was the “Mel Blount Rule” for illegal contact after five yards. That opened up the passing game, and the extended season opened up the opportunity to add volume to passing stats. Quarterbacks like Fouts and Dan Marino were among the first to take advantage.

But with strike-shortened seasons in 1982 and 1987, any chances of racking up huge counting statistics in consecutive years had to wait until 1988, which is when the run of uninterrupted 16-game seasons began.

It is no surprise decorated record holders like Brett Favre and Emmitt Smith started their careers shortly after 1988. They were among the first few elite talents to have the opportunity to string together so many consecutive 3,000-yard passing and 1,000-yard rushing seasons.

Throw in the low-volume offensive lull of the early 1990s, and it’s really with the free agency and salary cap era (1994-present) that we started to see the game open up offensively. It also helped that the success of the San Francisco 49ers with the West Coast Offense and short passes started to manifest around the league.

To this point, there have only been 33 seasons in NFL history with 16 games played. That’s 985 team seasons in the books.

With the quarterback position, if your starter is healthy and playing adequately to his level of experience, then he is going to keep playing each week. It’s when injuries or poor play set in that changes are made, which disrupts the statistics.

The 1999 Chicago Bears passed for 4,352 yards and 25 touchdowns, but no one noticed or cared because it was a 6-10 finish with the holy trinity of Shane Matthews, Cade McNown and Jim Miller combining to post those numbers.

Had only one quarterback finished with those statistics, he would have a franchise-record season for the Bears and might be remembered. But the numbers get lost when they are not collected by an individual quarterback.

This is why we broke down all 33 of the 16-game seasons by each team’s leading passer, which was determined by most passing yards in the regular season.

There were 14 teams where the quarterback leading in pass attempts did not lead in passing yards. The latest were the 2011-12 Cardinals with John Skelton leading in attempts, but Kevin Kolb leading in yards both seasons. The other 971 quarterbacks led in attempts and yards. Actually, there was one tie with Colin Kaepernick and Alex Smith each throwing 218 passes for the 49ers last year, but Kaepernick had the yardage tie-breaker.

This passing data only includes the regular season for all seasons with 16 games played:

NFL Passing Leader – Passing Totals (1978-12)

Year

Att.

Cmp.

Pct.

Yards

YPA

TD

INT

PR

1978

10004

5374

53.7

68449

6.84

406

507

67.8

1979

11274

6190

54.9

78083

6.93

481

506

72.2

1980

11806

6708

56.8

84075

7.12

529

525

75.5

1981

11284

6254

55.4

80812

7.16

497

447

76.3

1983

11101

6420

57.8

80801

7.28

513

472

78.3

1984

10617

6158

58.0

78785

7.42

494

398

81.2

1985

11190

6184

55.3

78835

7.05

489

449

75.3

1986

11058

6202

56.1

78151

7.07

438

414

75.9

1988

10543

5817

55.2

74530

7.07

437

379

76.4

1989

11421

6476

56.7

82507

7.22

480

418

78.2

1990

11087

6291

56.7

78926

7.12

487

364

80.0

1991

11054

6442

58.3

77658

7.03

402

350

78.8

1992

9923

5760

58.0

69666

7.02

401

359

78.1

1993

10948

6426

58.7

74079

6.77

398

343

78.3

1994

11664

6886

59.0

80348

6.89

475

353

80.9

1995

13858

8118

58.6

95485

6.89

577

384

81.9

1996

12643

7376

58.3

86070

6.81

518

422

78.8

1997

12238

6952

56.8

83253

6.80

507

339

80.0

1998

11459

6610

57.7

80247

7.00

519

352

81.6

1999

12375

7150

57.8

86452

6.99

520

400

79.9

2000

12852

7565

58.9

87861

6.84

525

410

79.9

2001

14187

8427

59.4

96770

6.82

560

463

79.6

2002

14181

8549

60.3

96660

6.82

584

404

82.6

2003

13393

7986

59.6

90536

6.76

548

431

80.2

2004

13519

8262

61.1

98395

7.28

637

401

86.7

2005

12913

7746

60.0

89456

6.93

535

369

82.8

2006

13603

8182

60.1

93412

6.87

536

412

81.3

2007

12853

8008

62.3

90841

7.07

574

389

85.7

2008

14197

8761

61.7

100236

7.06

571

358

85.8

2009

14238

8804

61.8

102548

7.20

630

415

86.2

2010

14418

8867

61.5

102788

7.13

649

398

86.5

2011

14578

8842

60.7

106554

7.31

657

402

86.6

2012

15646

9562

61.1

112537

7.19

697

401

87.2

The most interesting takeaway here is that the cumulative passer rating first surpassed 80.0 in 1984 (81.2). Thanks, Dan Marino. Remember, these are combined numbers for the one passing leader on each team.

When including every pass thrown in the season, the NFL did not surpass 80.0 in passer rating until 2002 (80.4). Yet it was hit six different times before that season by just the passing leaders.

This proves it is inferior backups and trick plays from non-quarterbacks that drag down the league’s passing stats each year. Every team wants to play its best quarterback as much as they can, but few ever make all 16 starts for various reasons.

While completion percentage has gone up and interception percentage has gone down, we have not seen any significant improvement with yards per attempt, which is one of the most crucial passing stats in the game. The same can be said for touchdown percentage.

The 2012 season offered the best passer rating (87.2) from the passing leaders. Was that just a sign of the times, or was there something more to it?

Next is a look at how many games the leading passer played, started, his record as a starter, average age and the percentage of total passes the leading passers attempted that season (Pass%).

NFL Passing Leader - Totals (1978-12)

Year

Games

Starts

Record

Win%

Avg. Age

Pass%

2012

467

451

240-214-1

0.529

27.9

87.96%

2001

458

448

233-215-0

0.520

29.3

87.68%

1979

420

399

204-195-0

0.511

28.8

86.86%

1980

414

398

202-194-2

0.510

28.9

86.14%

2008

460

446

240-204-2

0.540

28.8

85.91%

1978

412

389

201-186-2

0.519

28.5

84.57%

2011

443

434

230-201-0

0.534

27.5

83.73%

2009

450

437

239-198-0

0.547

28.3

83.59%

2010

443

429

225-204-0

0.524

29.1

83.49%

2006

460

435

230-205-0

0.529

28.3

83.00%

1995

441

422

222-200-0

0.526

29.8

82.99%

2004

439

425

228-197-0

0.536

28.3

82.66%

1990

402

385

204-181-0

0.530

28.3

82.03%

2002

450

424

223-199-2

0.528

28.3

82.01%

2003

435

421

218-203-0

0.518

28.7

81.20%

1989

389

363

189-173-1

0.522

28.8

79.66%

1981

399

382

200-180-2

0.526

29.4

79.58%

1991

390

366

189-177-0

0.516

29.0

79.23%

1996

415

395

208-187-0

0.527

30.6

79.19%

1983

394

376

193-182-1

0.515

29.0

79.03%

2000

430

411

214-197-0

0.521

28.3

78.74%

2005

434

418

222-196-0

0.531

29.0

78.43%

1997

414

399

205-190-4

0.519

29.1

77.81%

1985

399

360

187-173-0

0.519

28.6

77.58%

1994

389

363

195-168-0

0.537

29.6

77.47%

1986

386

351

174-175-2

0.499

27.6

76.43%

1993

387

359

188-171-0

0.524

29.7

75.95%

2007

414

395

217-178-0

0.549

29.7

75.41%

1988

372

345

182-161-2

0.530

27.8

74.61%

1984

393

355

184-169-2

0.521

28.8

74.12%

1992

375

350

191-159-0

0.546

29.1

74.01%

1998

391

363

196-167-0

0.540

30.5

73.98%

1999

415

373

191-182-0

0.512

29.7

73.84%

Sure enough, the 2012 season leads the way with 87.96 percent of all passes thrown last year coming from just the 32 leading passers.

The 2012 season also has a record 451 starts from the leading passers. As Chase Stuart notes, 2012 was unusually “healthy” with 20 quarterbacks starting all 16 games.

When you can eliminate so many backup scenarios, that should in theory produce better passing statistics.

The average Pass% was 80.34 percent. Here is the year-by-year graphical representation of Pass%:

Things started high in 1978-80, but soon enough it dipped below 80 percent for most seasons until resurgence in 2001. It helps to have quarterbacks who rarely miss starts like Brett Favre, the Manning brothers and Tom Brady, but that’s still a small fraction.

Clearly, more teams are now being led by a quarterback that accounts for most of their pass attempts. The last four seasons all rank in the top nine seasons for Pass%.

The 1986 season was the only time the passing leaders had a record under .500 (174-175-2). These would all even out to .500 when including everyone, but this does tell us the backups/secondary passers are losing much more often than winning (except in 1986).

When it comes to age, the passing leaders are an average 28.9 years old. The youngest season was 2011 with 27.5 years old. The 2012 season is not far behind at No. 4 (27.9). Obviously we have a youth movement at the position with Andrew Luck, Robert Griffin III, Russell Wilson, Ryan Tannehill, Cam Newton, Andy Dalton, Colin Kaepernick and Matthew Stafford.

The oldest season was 1996 at 30.6 years old. The 1995-99 range included the four oldest seasons when the NFL was getting ready to have a transition period as veterans like Dan Marino, Warren Moon, Jim Kelly, Steve Young, Troy Aikman, John Elway were on their way to retirement.

Here is a look at the passing averages for the leading passer, sorted by descending pass attempts:

NFL Leading Passer Averages (1978-12)

Year

Starts

Comp.

Att.

Yards

TD

INT

2012

14.1

298.8

488.9

3516.8

21.8

12.5

1995

14.1

270.6

461.9

3182.8

19.2

12.8

2001

14.5

271.8

457.6

3121.6

18.1

14.9

2011

13.6

276.3

455.6

3329.8

20.5

12.6

2010

13.4

277.1

450.6

3212.1

20.3

12.4

2009

13.7

275.1

444.9

3204.6

19.7

13.0

2008

13.9

273.8

443.7

3132.4

17.8

11.2

2002

13.3

267.2

443.2

3020.6

18.3

12.6

2006

13.6

255.7

425.1

2919.1

16.8

12.9

2004

13.3

258.2

422.5

3074.8

19.9

12.5

1980

14.2

239.6

421.6

3002.7

18.9

18.8

1996

13.2

245.9

421.4

2869.0

17.3

14.1

2003

13.2

249.6

418.5

2829.3

17.1

13.5

1994

13.0

245.9

416.6

2869.6

17.0

12.6

2000

13.3

244.0

414.6

2834.2

16.9

13.2

1997

13.3

231.7

407.9

2775.1

16.9

11.3

1989

13.0

231.3

407.9

2946.7

17.1

14.9

2005

13.1

242.1

403.5

2795.5

16.7

11.5

1981

13.6

223.4

403.0

2886.1

17.8

16.0

1979

14.3

221.1

402.6

2788.7

17.2

18.1

2007

12.3

250.3

401.7

2838.8

17.9

12.2

1985

12.9

220.9

399.6

2815.5

17.5

16.0

1999

12.0

230.6

399.2

2788.8

16.8

12.9

1983

13.4

229.3

396.5

2885.8

18.3

16.9

1990

13.8

224.7

396.0

2818.8

17.4

13.0

1986

12.5

221.5

394.9

2791.1

15.6

14.8

1991

13.1

230.1

394.8

2773.5

14.4

12.5

1993

12.8

229.5

391.0

2645.7

14.2

12.3

1998

12.1

220.3

382.0

2674.9

17.3

11.7

1984

12.7

219.9

379.2

2813.8

17.6

14.2

1988

12.3

207.8

376.5

2661.8

15.6

13.5

1978

13.9

191.9

357.3

2444.6

14.5

18.1

1992

12.5

205.7

354.4

2488.1

14.3

12.8

Again, 2012 quarterbacks lead the way with an average of 488.9 pass attempts. Contrast that with 1992 when the leading passers only averaged 354.4 pass attempts. It is not much of a surprise only Dan Marino (4,116 yards) was able to surpass 3,500 passing yards that season.

Last season, 18 quarterbacks attempted at least 500 passes. In 1992, only Marino (554) did, and only 11 quarterbacks surpassed just 400 attempts.

It all comes back to opportunity, which in the case of a quarterback is pass attempts.

Random Musings

Finally, here are some random musings discovered in this dataset.

How in the hell did Kerry Collins convince Jim Fassel (2000-03 Giants) and Norv Turner (2004-05) to let him throw at least 500 passes in six consecutive seasons?

That is almost as odd as Tony Banks and Joey Harrington leading a team in passing six times each. Jim “Captain Comeback” Harbaugh leading a team in passing 10 times was the biggest surprise out of the 22 names with double-digit seasons.

Then we have the teams that did it right year after year.

The Denver Broncos have had a quarterback start at least 10 games in 30 consecutive seasons (1983-present). Peyton Manning is the seventh player to extend that streak, which started with John Elway’s rookie year.

The next best streaks (still active) belong to the Steelers and Packers (21 seasons each since 1992). The Patriots (20 seasons since 1993) are next.

Since 1993, the Broncos, Steelers, Packers and Patriots have combined for nine of the 20 Super Bowl wins and six Super Bowl losses. Great quarterback stability pays off.

The 1995 expansion teams, Carolina and Jacksonville, have actually had a quarterback start 10+ games in every season but one (2007 Panthers). A 44-year-old Vinny Testaverde led the team with six starts and 952 yards, which might be the most improbable – definitely the most geriatric – passing leader of the 985 studied.

Only two other teams have been led by a quarterback with less than 1,000 yards in a 16-game season: 2004 Bears (Chad Hutchinson, 903 yards) and 2005 49ers (Alex Smith, 875 yards).

The fact that Chad Hutchinson has led two different teams in passing (2002 Cowboys and 2004 Bears) is simply outstanding.

With that happening in an era when we glorified the likes of Trent Green, Daunte Culpepper and Steve McNair as elite quarterbacks, how can anyone not acknowledge the golden era we currently enjoy?

Conclusion: Numbers Should Continue to Rise

If everything went according to plan, we could have 19 quarterbacks throw for 4,000 yards in 2013. Of course, things never go as planned. Players will get hurt. Players will disappoint. That’s just the nature of the NFL.

Though as long as teams remain quarterback dependent, there is no reason the passing numbers will not get better. We may only be a few seasons away from the league-average passer rating crossing the 90.0 mark with the average team passing for 4,000 yards.

Besides, is averaging 250 yards per game on 35-plus attempts per game really that difficult or incredible to do?

If teams continue to inflate the pass ratio with short passes that will boost completion percentage, decrease interceptions and add a few shorter touchdown throws at the goal line, then that alone can make up the difference to get above 90.0.

The increased workload does not mean the quarterback of today’s job is easier, but it sure is different.

Some teams will still struggle. Minnesota’s Christian Ponder had a hell of a time surpassing 100 yards in multiple games last season, and three times he failed to do it. We still see teams like the 2012 Chiefs and 2011 Rams finish a full season with single-digit touchdown passes while Matt Flynn threw nine in two starts as Aaron Rodgers’ backup in Green Bay.

Today’s amazing stats do not discredit what past quarterbacks like Ken Anderson or Roger Staubach did in the dead-ball era of the 1970s. We just have to be smart about how those players are compared, because the game was so much different back then.

Comparing a 2013 quarterback straight up to a dead-ball (or older) quarterback may be as beneficial as comparing a 19th-century aristocrat to a caveman.

Quarterbacks and offensive football have evolved, and the statistics reflect that. Even then, something as simplistic as starting as many games as possible for your team is still very important in amassing numbers.

As taught in Football Stats 101, the best quarterbacks tend to produce the best statistics. The more often the backups stay on the bench, the better.

Last year may just be a fluke, but if the NFL’s changes allow for better quarterback health, then with the record number of pass attempts coming from the uniquely talented leading passers, we can count on the league records being rewritten on an annual basis.

Teams just have to avoid those Curtis Painter or Caleb Hanie situations. No one wins (except their opponents) when a team is forced to go that direction.

Scott Kacsmar is a football writer/researcher who has contributed large quantities of data to Pro-Football-Reference.com, including the only standardized database of fourth quarter comebacks and game-winning drives. You can visit his blog for a complete writing archive. Please send any questions or comments to Scott at smk_42@yahoo.com, or you can follow him on Twitter at @CaptainComeback.